The six gases, namely, (1) carbon dioxide (CO2), (2) methane (CH4), (3) nitrous oxide (N2O), (4) hydrofluorocarbons (HFCs), (5) perfluorocarbons (PFCs), and (6) sulfur hexafluoride (SF6), present in the atmosphere are called greenhouse gases (GHGs). These gases retain infrared radiation in the atmosphere, warm the earth’s surface and the lower part of the atmosphere, and contribute to the GHG effect required to maintain balanced warming of the earth. In their absence, the mean temperature of the earth would be about −19°C rather than the present mean temperature of about 15°C. The world is now aware that various human-induced activities like industrialization, agricultural practices, urbanization, and animal domestication have disturbed the natural balance of these gases and led to increased GHG emissions in the atmosphere. GHG-induced ...